BRENTWOOD — Prosecutors say murder victim Amanda “Amy” Warf’s ex-husband used a gun to force her into the abandoned concrete plant in Exeter where she met her demise.

The state attorney general’s office on Friday laid out new details about the alleged plot to kill Warf, which was said to be in the works as early as January.

Warf’s former husband of seven years, Aaron Desjardins, of Epping, is facing first-degree murder charges in the case. Prosecutors say Desjardins conspired with his new wife, Sarah Desjardins, and a sister living in Maine to kill Warf.

Aaron Desjardins is accused of killing Warf in March by slitting her throat and severing an artery. Firefighters found her body inside an abandoned concrete plant on Hampton Road in Exeter on Thursday morning, March 7, after the building caught fire.

Investigators say before the murder, Sarah Desjardins sent a text message to her husband’s sister asking her to bring a “roasting pan” to New Hampshire. The words were allegedly a code meaning that the sister, 43-year-old Michelle Corson, should bring a gun to the state. Aaron Desjardins, who suffers from multiple sclerosis, allegedly used the weapon to force Warf to enter the concrete plant where her body was found.

In arguments before a trial court judge Friday, Sarah Desjardins’ attorney did not dispute that her client sent the message, but instead, made the case that Sarah Desjardins was unaware that “roasting pan” was a reference to a firearm.

Sarah Desjardins is charged with conspiracy to commit murder and conspiracy to commit hindering apprehension or prosecution. She appeared in circuit court in Brentwood Friday morning for a bail reduction hearing and probable cause hearing.Aaron Desjardins told investigators the plot to kill his ex-wife was hatched in collaboration with Sarah Desjardins, according to prosecutor Jay McCormack, a staffer at the attorney general’s office, who told the judge that the pair discussed the plan at least 10 times. Sarah Desjardins also allegedly advised her husband of which sweater he should wear during the crime, in order to dispose of it after the fact.

“This was a conspiracy that took place over the course of months,” he said.

Sarah Desjardins, of 67 Railroad Ave., Epping, is also accused of providing a false alibi to police about her husband’s whereabouts on the morning of March 7.

Her attorney disputed that Desjardins had knowledge of the murder plot, explaining that Sarah Desjardins might have been aware of her husband’s “homicidal ideation,” but didn’t realize his intent to act upon it. She requested for bail to be reduced to $5,000 cash.

A judge ultimately agreed with a request from the state prosecutors, ordering Sarah Desjardins to be held on $50,000 cash or corporate surety bail. She also waived her right to a probable cause hearing, sending her case to a grand jury.

Senior Assistant Attorney General Susan Morrell has declined to comment on the manner in which police believe Aaron Desjardins killed his former spouse, who is also the mother of his one-year-old son. Morrell said Warf’s wounds were horizontal and “deep into the tissue.”

In the days that followed Warf’s murder, Aaron Desjardins repeatedly told reporters he was innocent of the crime. Meanwhile, homicide investigators were scouring his property. He was then arrested on Tuesday, March 12.Corson, Aaron Desjardins’ sister, has also been charged in the case. She was arrested in Skowhegan, Maine, last week on a fugitive from justice charge. New Hampshire authorities have charged Corson with conspiracy to commit murder and being an accomplice to first-degree murder. Corson has waived her right to challenge extradition to New Hampshire, McCormack said in court Friday.Family court records in Brentwood indicate Warf and Aaron Desjardins were married for about seven years before separating in 2011. They shared the home on Railroad Avenue that Aaron Desjardins now owns. His divorce from Warf was finalized early last year, and Desjardins married Sarah Desjardins around the same time, according to court records.A lawyer who was previously representing Aaron Desjardins in negotiations in family court said Warf and Desjardins were finalizing a parenting agreement for their child at the time of Warf’s death.